1. Field of the Invention
The present invention relates to a printing apparatus and a printing system.
2. Description of the Related Art
Recently, techniques for processing and printing color image data have advanced, and systems for such purposes are rapidly spreading. Printing apparatus used in such systems employ various methods of printing. Above all, inkjet printing apparatus have come in use in a wide variety of applications such as printing terminals of systems and printing sections of copying machines and facsimile machines for the reasons that they generate little noise during printing, that the apparatus themselves are inexpensive and their running cost is small, and that the apparatus are small in size.
Recently, there is a significant trend toward diversification of input units that supply printing data to printing apparatus. Scanners, digital cameras, and even simple memory cards are frequently used as such units, to say nothing of personal computers. In addition, printing apparatus have come in use in a variety of environments such as offices and homes that are, so to speak, static environments in which the apparatus are connected to those input units and dynamic environments in which the apparatus are used as mobile apparatus. Therefore, printing apparatus are required to be connectable to various input units and, desirably, they are able to print printing data supplied from input units connected thereto in an optimum mode.
Printing apparatus employing the dot matrix printing method are the main trend because they are capable of printing at a high speed or high quality at a low cost. However, there is a significant recent trend toward printing dots with smaller diameters in order to obtain images with higher quality and higher definition, and this has resulted in more strict regulation of alignment between the printing positions of dots in respective tones (hereinafter also referred to as registration). The term“dot position aligning” implies a process of making corrections to align the printing positions of dots in respective tones when printing agents in a plurality of tones (the term“tones” implying colors and densities) are used. The term“dot position aligning” also implies even a process involved in printing in a single tone where corrections are made to align the printing positions of dots when printing is performed in both of a forward scanning and a reverse scanning, for example, in a serial printing method.
A process for performing such registration with high accuracy is disclosed in Japanese Patent Application Laid-open No. 10-264485 (1998). There is disclosed a technique in which a check pattern for a low resolution condition is printed substantially in the middle of a printing medium; an adjustment is made based on the pattern; and a check pattern for a high resolution condition is thereafter printed in a position in which no interference with the above check pattern occurs; and another adjustment is made based on the same. While the disclosure primarily describes applications in inkjet printing apparatus, the technique is obviously applicable to other dot matrix type printing apparatus or methods and is advantageous also in thermal transfer type printing apparatus or methods utilizing an ink sheet in the form of a film, for example.
A setting for registration has been commonly made by a printing apparatus in response to activation by a printer driver of a computer or made by the computer through a process of adapting image data supplied by itself to the mode of printing. Recently, however, there are various input units for supplying printing data, and printing apparatus are used in various environments as described above.
No problem occurs when a printing apparatus is used by connecting it to a host apparatus which can supply image data after making adjustments for registration by itself or when a printing apparatus is configured to be able to make a setting for registration in response to a request from a host apparatus. However, a printing apparatus may be connected to a host apparatus which cannot supply adjusted data or transmit a request for a process of making a setting for registration depending on the environment in which they are connected. For example, digital cameras (including those integrated with mobile telephones in addition to standalone products) and scanner apparatus are rapidly spreading. In order to achieve compactness and light weights, those apparatus are frequently configured without even the capability of transmitting a request for the setting process for registration, not to speak of supplying adjusted data to a printing apparatus. In particular, when printing is performed without the intervention of a host apparatus such as when data are printed by simply reading them from a memory card directly, the setting process for registration may not be performed at all depending on the configuration of the printing apparatus. Furthermore, in the case of a low-cost printing apparatus, it may not be configured to allow itself to perform the setting process for registration and to perform a process of correcting dot forming positions, and printing will be performed with no correction at all when no host apparatus is used.